1. Field of the Invention
The present invention generally relates to an organic electroluminescent device having a thin film encapsulation structure, and more particularly, to an organic electroluminescent device having a thin film encapsulation structure, in which an inorganic layer and an organic layer are stacked, and a method of fabricating the same.
2. Description of the Related Art
Encapsulation technology of an organic light-emitting device may include substrate bonding technology for bonding an encapsulation substrate and a substrate having an organic light-emitting device formed thereon to each other, and a thin film encapsulation technology for forming an encapsulation layer in the form of a thin film without an encapsulation substrate. The bonding of the encapsulation substrate and the substrate having an organic light-emitting device formed thereon is performed by using an inorganic frit or an organic adhesive. An inorganic layer, such as AlOx, SiNx, SiOx, and SiON, on a panel may be used for thin film encapsulation.
An inorganic layer for thin film encapsulation is thin, but a density thereof is high, and thus, the inorganic layer for thin film encapsulation may have barrier characteristics with respect to moisture and oxygen. However, since an inorganic layer has brittle characteristics, mechanical properties thereof under stress may be poor. In particular, a plurality of particles may exist on a substrate during a process of fabricating an organic light-emitting device, and an inorganic layer disposed on the particles may be significantly affected by stress, and thus, the barrier characteristics of the inorganic layer may be degraded.
Therefore, a structure is introduced for planarizing an irregular surface, such as particles, by introducing an organic layer between the inorganic layers as well as relieving the stress of the inorganic layer. Acryl, silicone, and epoxy are used as the organic layer.
In general, thermal stability must be maintained at about 100° C. for the reliability of the organic light-emitting device. However, a phenomenon of peeling-off of an interface between the inorganic layer and the organic layer may occur during exposure at a high temperature for a prolonged period of time. For example, since strong chemical bonding may be difficult to be formed in the case where an acryl layer is deposited on a SiNx layer deposited through a plasma enhanced chemical vapor deposition (PECVD) process, an interface between the SiNx layer and the acryl layer may be peeled off due to heat.